SRC/dlasyf_aa.f(3)

💖 SRC/dlasyf_aa.f(3) — Library Functions Manual 💖

okay bestie, this is the Library Functions Manual page for SRC/dlasyf_aa.f(3). Pull up a chair, we're getting into the dlasyf_aa of it all 🫶

🌸 NAME 🌸

SRC/dlasyf_aa.f — literally the name of this page, no cap.

✨ SYNOPSIS ✨

🌟 Functions/Subroutines

• subroutine dlasyf_aa (uplo, j1, m, nb, a, lda, ipiv, h, ldh, work) — DLASYF_AA

subroutine dlasyf_aa (uplo, j1, m, nb, a, lda, ipiv, h, ldh, work)

DLASYF_AA

💅 Function/Subroutine Documentation 💅

Here's the exact signature, bestie — punctuation stays exactly where it is:

subroutine dlasyf_aa (character uplo, integer j1, integer m, integer nb,
    double precision, dimension( lda, * ) a, integer lda, integer,
    dimension( * ) ipiv, double precision, dimension( ldh, * ) h, integer
    ldh, double precision, dimension( * ) work)

DLASYF_AA

🎀 Purpose 🎀

okay so DLATRF_AA factorizes a panel of a real symmetric matrix A using the Aasen's algorithm. The panel consists of a set of NB rows of A when UPLO is U, or a set of NB columns when UPLO is L.

In order to factorize the panel, the Aasen's algorithm requires the last row, or column, of the previous panel. The first row, or column, of A is set to be the first row, or column, of an identity matrix, which is used to factorize the first panel.

The resulting J-th row of U, or J-th column of L, is stored in the (J-1)-th row, or column, of A (without the unit diagonals), while the diagonal and subdiagonal of A are overwritten by those of T.

🌈 Parameters 🌈

• UPLO — UPLO is CHARACTER*1. Set it to 'U' when the upper triangle of A is stored; set it to 'L' when the lower triangle of A is stored.
• J1 — J1 is INTEGER. This is the location of the first row, or column, of the panel within the submatrix of A, passed to this routine. For example, when called by DSYTRF_AA, for the first panel, J1 is 1, while for the remaining panels, J1 is 2.
• M — M is INTEGER. The dimension of the submatrix. M >= 0.
• NB — NB is INTEGER. The dimension of the panel to be facotorized.
• A — A is DOUBLE PRECISION array, dimension (LDA,M) for the first panel, while dimension (LDA,M+1) for the remaining panels.
  • On entry, A contains the last row, or column, of the previous panel, and the trailing submatrix of A to be factorized; except for the first panel, only the panel is passed.
  • On exit, the leading panel is factorized.
• LDA — LDA is INTEGER. The leading dimension of the array A. LDA >= max(1,M).
• IPIV — IPIV is INTEGER array, dimension (M). Details of the row and column interchanges: the row and column k were interchanged with the row and column IPIV(k).
• H — H is DOUBLE PRECISION workspace, dimension (LDH,NB).
• LDH — LDH is INTEGER. The leading dimension of the workspace H. LDH >= max(1,M).
• WORK — WORK is DOUBLE PRECISION workspace, dimension (M).

👑 Author 👑

• Univ. of Tennessee
• Univ. of California Berkeley
• Univ. of Colorado Denver
• NAG Ltd.

Definition at line 142 of file dlasyf_aa.f.

🌟 Author 🌟

Generated automatically by Doxygen for LAPACK from the source code.

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Mwah 💋 — cute little sign-off time: this page says LAPACK Version 3.12.0 and SRC/dlasyf_aa.f(3). The footer doesn't give a separate date, so that's the whole vibe, bestie. Stay factorized 💅✨